Physical characterization and performance evaluation of an x-ray micro-computed tomography system for dimensional metrology applications

Hiller, Jochen; Maisl, Michael; Reindl, L.

doi:10.1088/0957-0233/23/8/085404

Cited by 100 publications

(54 citation statements)

References 44 publications

(58 reference statements)

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“…The good short-term repeatability observed in CT measurements and the relevant role played by the bias, are in consonance with results reported by other authors [6][7]. The estimated biases, clearly affected by edge-related determination errors, lie within the empirical error band proposed by the authors in a recent paper [4], and therefore reinforce their estimation.…”

Section: Discussionsupporting

confidence: 91%

Experimental evaluation of the uncertainty associated with the result of feature-of-size measurements through computed tomography

Fernandes

Donatelli

Baldo

2016

J. Phys.: Conf. Ser.

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Abstract.Computed tomography for dimensional metrology has been introduced in quality control loop for about a decade. Due to the complex measurement-error cause system, generally no consistent measurement uncertainty reporting has been made. The ISO 15530-3 experimental approach, which makes use of calibrated parts, has been tested for estimating the uncertainty of CT-based measurements of features of size of a test object made of POM. Particular attention is given to the design of experiment and to the measurement uncertainty components. The most significant experimental findings are outlined and discussed in this paper. IntroductionComputed tomography (CT) for industrial coordinate metrology has been part of dimensional quality control loop for about a decade. In general, complex-shaped parts with hundreds (even thousands) of features (hidden features as well) can be holistically inspected with great operational advantages over other existing coordinate metrology technologies, such as tactile and/or optical coordinate measuring machines.CT measurement principle relies on the attenuation of X-rays when propagating through the test object, which depends on the object material and radiographic thickness. For a large number of beam directions, the intensity distribution of the remaining radiation is measured and digitally stored as a grey-value image. The resulting projections of the full object rotation are mathematically processed to create the 3D voxel matrix. Further processing steps over the voxel data allow performing dimensional measurements.The CT principle and the metrological CT scanner setup give rise to influence factors that affect the performance of dimensional evaluations. They are related to the source (e.g. photon energy, focal spot size), to the detector (e.g. sensitivity, pixel size, exposure time, averaging), to the object (e.g. material, shape, size), to the CT kinematics (e.g. magnification axis and turntable repeatability and accuracy), and mathematical data processing (e.g. segmentation, measuring strategy) [1].Due to that intricate measurement-error cause system, establishing traceable measurements with CT has been pointed as a key metrology issue. This paper outlines and discusses the use of calibrated workpieces, as specified in part 3 of ISO 15530, for estimating the task-specific uncertainty associated

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Section: Discussionsupporting

confidence: 91%

Experimental evaluation of the uncertainty associated with the result of feature-of-size measurements through computed tomography

Fernandes

Donatelli

Baldo

2016

J. Phys.: Conf. Ser.

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“…X-ray CT collects a series of radiographs through a 360-degree rotation of the work-piece that are then reconstructed to create a 3D model of the examined object. The produced X-rays need to have sufficient energy to penetrate the examined object and travel to the detector where the radiographs are collected [22]. In a well-calibrated CT system, the quality of the radiographs depends on the characteristics of the X-rays, the settings of the detector and the exposure time per radiograph.…”

Section: Computed Tomographymentioning

confidence: 99%

Computed tomography metrological examination of additive manufactured acetabular hip prosthesis cups

Kourra

Warnett

Attridge

et al. 2018

Additive Manufacturing

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A B S T R A C TAdditive manufacturing (AM) is uniquely suitable for healthcare applications due to its design flexibility and cost effectiveness for creating complex geometries. Successful arthroplasty requires integration of the prosthetic implant with the bone to replace the damaged joint. Bone-mimetic biomaterials are utilised due to their mechanical properties and porous structure that allows bone ingrowth and implant fixation. The predictability of predetermined interconnected porous structures produced by AM ensures the required shape, size and properties that are suitable for tissue ingrowth and prevention of the implant loosening. The quality of the manufacturing process needs to be established before the utilisation of the parts in healthcare. This paper demonstrates a novel examination method of acetabular hip prosthesis cups based on X-ray computed tomography (CT) and image processing. The method was developed based on an innovative hip prosthesis acetabular cup prototype with a prescribed non-uniform lattice structure forming struts over the surface, with the interconnected porosity encouraging bone adhesion. This non-destructive, non-contact examination method can provide information of the interconnectivity of the porous structure, the standard deviation of the size of the pores and struts, the local thickness of the lattice structure in its size and spatial distribution. In particular, this leads to easier identification of weak regions that could inhibit a successful bond with the bone.

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“…The collected CT data has been proven to be possibly influenced by bi-directional repeatability of the system, radial run-out errors, the detector tilt and type and the movement of the spot size of the X-ray in the duration of a scan [34][35][36][37][38]. The reduction of artefacts in affected data can be achieved by following the recommendations provided by VDI/VDE 2630 Part 1.4; a guide to obtain dimensional measurements through CT [39].…”

Section: X-ray Computed Tomographymentioning

confidence: 99%

Metrological study of CFRP drilled holes with x-ray computed tomography

Kourra

Warnett

Attridge

et al. 2015

Int J Adv Manuf Technol

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The popularity of composite materials is continuously growing with new varieties being developed and tested with different machining processes to establish their suitability. Destructive as well as non-destructive methods, such as ultrasonics, X-ray radiography and eddy-current, have previously been used to ensure that the combination of particular machining methods and composites provide the required quality that can allow the required lifespan of the final product. X-ray computed tomography (CT) is applied as a novel method in this paper to obtain quantitative data about the inner and outer structures of carbon fibre reinforced polymer (CFRP) drilled holes providing more information than any other non-contact and non-destructive evaluation. This is combined with precise measurements from optical CMM and image processing for a full analysis for the entire part. This method can provide accurate measurements for all the layers of the CFRP and very little interaction from the operator minimising the human error. The method complies with VDI/VDE 2630 standard and the quality of the acquired measurements is assured. The results can assist in establishing the best machining process, provide accurate measurements of diameter, circularity and positioning of the hole and information about delaminated areas.

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Physical characterization and performance evaluation of an x-ray micro-computed tomography system for dimensional metrology applications

Cited by 100 publications

References 44 publications

Experimental evaluation of the uncertainty associated with the result of feature-of-size measurements through computed tomography

Experimental evaluation of the uncertainty associated with the result of feature-of-size measurements through computed tomography

Computed tomography metrological examination of additive manufactured acetabular hip prosthesis cups

Metrological study of CFRP drilled holes with x-ray computed tomography

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